A shotgun shell is a “a self-contained cartridge typically loaded with multiple metallic ‘shot’, which are small, generally spherical projectiles.”
Shotguns are also capable of firing a single projectile, called a ‘slug’.
A shotgun shell is cased in plastic with a brass base containing the primer.
Starting at the brass, the layers of a shotgun shell are brass, propellant, over-powder wad, shot wad, shot pellets (or slug), over-shot wad, and top crimping.
The brass base of the shell is thick enough to hold the primer, which is longer than those used for rifle and pistol ammunition.
Okay, we threw a bunch of unfamiliar terms at you in the above description of a shotgun shell. Don’t worry, we’ll define each of them for you so you’ll have a better understanding of shotgun shells and how all the parts work together.
Bore–the interior diameter of a tube or cylinder, in this case, the inside of the shotgun barrel.
Shot–the pellets inside some shotgun pellets. These range in size and number according to their usage.
Wadding or Wad–this prevents the shot and powder from mixing, and provides a seal to keep gas from blowing through the shot instead of pushing it forward.
Slug–a single projectile round in a shotgun shell, used for hunting larger game.
Sabot–a plastic shell around some shotgun shells, which give the projectile a degree of spin as it leaves the barrel.
Rifling–spiral-like casts on the inside of some shotgun barrels, these are paired with saboted slugs to increase the slug’s rotation as it leaves the barrel. Handgun barrels are also rifled.
Brass–the part of the shotshell containing the primer.
This is an old term that refers to the barrel diameter.
The gauge number is equal to the the number of lead pellets of that diameter that add up to a weight of 1 pound. The most common gauge in use in the U.S. is the 12 gauge, but there are also 28, 20, 16, and 10 gauge.
10 and 16 gauge shotshells are rare, though they’re still being manufactured.
Shotguns using 11, 15, 18, 2, and 3 gauge shells are the most rare of all the shotguns, and shotshells for these are no longer manufactured. Owners of these firearms usually have a specialist hand load the shells.
The .410 round is not a gauge; instead, it is measured in caliber, though the weapon that fires it is still a shotgun. But, the .410 shotshell is still encased in a plastic shell, just like other shotshells.
Together, all the pellets in a shotgun shell are called the shot. These projectiles are usually made of lead, but can also be lead-coated steel, tungsten or bismuth.
Shot sizes are measured with numbers starting with the smallest, which is ‘birdshot’.
Eventually the numbers change to letters until you reach the largest, which is called ‘buckshot’, a popular large-game round.
Main Shot Types:
Pest: The lightest shot size is called ‘Dust’ and is used for pests. #12, #11, and #10 shot is also used for pests.
Birds/Skeet: #9 ½ to #7 ½ are used for birds or clay targets (called skeet).
Birds: #7 to #1 and B through BBB are used for birds.
Waterfowl: T, TT, TTT (or F), and FF are used for waterfowl.
Deer/Larger Game: Buckshot is #4 through #1 ½ and 0 to 0000. 00 is often shortened to ‘double-aught’ and 000 is sometimes called ‘triple-aught’ shot.
Now before my inbox fills up with angry emails, let me say that these rules are not set in stone. You’re free to hunt any game with any cartridge, permitting your local and state laws.
That said, the above are a good rule-of-thumb which you can reference any time you’re preparing for a hunt.
Next up: slugs.
Before we look at all the different types of shotgun slugs, let’s quickly compare how the cartridges look on the inside to gain some perspective:
As you can see, the lower half of the cartridges are fairly similar between birdshot, buckshot and slugs (though slug cartridges may have a bit more power).
The difference is in the projectile itself.
Full-bore Slugs: 5 Major Types
These are single projectile shotgun rounds used for hunting larger game animals. There are a lot of different types of slug.
Some shotguns have a slight rifling of the barrel, while other shotguns have no rifling and are referred to as smoothbore. Saboted slugs are designed for the barrel rifling and use a shuttlecock method to keep them stable.
1. BRENNEKE SLUGS
This is a solid lead slug with ribbing on the outside. These ribs allow a small amount of rotation as the slug moves down the barrel.
They also reduce friction in the barrel, increasing the slug’s velocity. This slug is solid and provides deep penetration.
2. FOSTER SLUGS
The Foster slug is intended to be fired through a non-rifled shotgun barrel. It has a deep hollow in the rear of the slug, like that in the back of an airgun pellet.
They also have ribbing down the sides to give the slug a slight rotation and improving precision.
These slugs are roll-crimped at the end, making them impossible to hand reload without the use of special tools.
3. SABOTED SLUGS
These slugs are smaller than the bore or diameter of the shotgun and are wrapped in a plastic ‘sabot’. This sabot is designed to engage with the rifling in the shotgun barrel and give a ballistic spin to the projectile.
Because the sabot prevents the slug from touching the bore, the projectile can be made from lead, copper, brass, or steel. They vary in shape but are usually bullet shaped.
The sabot keeps the projectile in the center of the bore as it rotates, and peels away from the slug one it leaves the barrel. These offer increased accuracy.
4. WAD SLUGS
These are modern variations between the Foster and saboted slugs. Wad slugs are also sometimes called ‘drive key’ or ‘key’ slugs.
It’s designed to fire through a smooth bore and is shaped more like a bullet with a smooth outer surface. A wad slug is loaded using a standard shotshell wad, which prevents lead fouling even when fired through a rifled barrel.
Wad slugs have accuracy at a distance range of about 75 yards (70 meters), which puts them in the same category as the Foster slug.
Traditional sabots can be accurate at greater distances. Wad slugs are also crimped with a fold at the end, making them easier to hand reload using a press without specialized tools.
5. PLUMBATA SLUGS
This slug has a plastic stabilizer as part of the slug. It might be either stuck into a cavity at the bottom of the projectile or over the slug in external notches.
With the stabilizer in the rear of the slug, discarding sabots can be included. In the second type of Plumbata slug, the stabilizer itself acts as a sabot but remains part of the slug until impact (Impact Discarding Sabot).
Shotshells come in a variety of lengths. This is important to keep in mind because firing a shell longer than a shotgun’s chamber can be dangerous, even if it’s the correct gauge.
Modern 12-gauge shotshells come in 2 ½-, 2 ¾-, 3-, and 3 ½-inch lengths, all holding different amounts of powder. Shotguns are marked on the barrel, for example: 12-gauge 2 ¾ inch. This shotgun’s maximum shell length is 2 ¾ inches.
It’s also important to point out that you should never fire a gauge different than that of your shotgun. This can destroy a gun and lead to serious injury to both the shooter and any innocent bystanders.
Always check the shell and the shotgun for compatibility.
High and Low Brass
A myth arises because shotgun shells have different sizes of brass.
So-called ‘high brass’ shells are thought to contain more powder, making them more powerful.
This may have been true at one point in the history of shotguns, but not any more.
When purchasing shotgun ammo, just ignore the brass length.
If you’re new to shotgun ownership, the variety of ammunition available is probably confusing.
It’s important to remember never to use shotgun shells in a different gauge as your shotgun, because this is extremely dangerous.
Your choice of shotshell will depend on many factors, including what type of hunting or shooting you plan to do.
Armed with your new knowledge, your next stop at the ammo store is going to be one heck of a good time!
Did I forget any shotgun ammo terms? Please let me know in the comments below.
Hey everyone I'm Chris. Founder and editor at Gun News Daily. This site was originally started by my father who passed it on to me. Gun News Daily has been reporting on gun news and conservative politics since 2001. We are the original gun news source. Life-long Second Amendment Supporter.